Piston skirt expander



Q:so

PatentedApr.- 12k,` 1.93.8

W. Wenzel,` deceased application-1und1?, .1936.; serial No. 85,711

i s claim.V 'torens- 12) j Myv inventiorrrelates.` to new, arid'fsefuiimprovements in pistonv skirt expande, ancl` has foran object to`provide a.'A simple `and, inexpensive v means for eflicientlyiexpandingthe skirts .of new or worn pistons.

I p, "Asjis well known'fto those-skilled]inl'thel'art, l slightly wornpistons have a tendency to #piston slap", and if the skirt can beexpanded fin an efiicient manner, the slappingrcan be overcome.

One of the principal objects of the present in- Y vention is A, toprovide f av piston skirt expander formedfromfa, properly temperedspring wire,

` the'expander having two` e'nci and two side por.` tions and loops or`eyelets formed both in the side `and in the'opposite end portions.`

' gstiuj another ,object of the `invention is to provide a piston skirtexpanderformedfrom properly tempered wir`` substantially .rectangular inform andhavingloops inibothlthe sides ,and the ends and'also arelativelyvlargeioopin each of the side portions that ilt aboutA thebearings in the piston vhead which`accommodate the wrist pins. I 'Stillanotherobject of the invention is to provide apiston skirt expanderformed ot wire that is to be pressed or snappedin position in the pistonskirt, this being possible in that the loops both in the sides and endsof the expander will compress when the piston expander is forced underslight presure into position. Then, after the expander is in position,`there will be a spreading action provided, which, although relativelylight, 's will tend to spread the skirts an additional five to twentyten-thousandths of an inch, which is usually suiiicient to prevent theobjectionable `slapping of the pistons.

Still another object of the invention is to provide an especiallyresilient form of skirt expander ',havingnintegral loopsin the sides ofthe expander as` well as `in the end portions, so that the expander willtend to expand the piston skirt in an eii'icient manner.

Still another object of the invention' is to proi vide a piston skirtkexpander in which it is not necessary to have any adjustable parts, theexpander being exceedingly flexible and, therefore,

capable of being compressed while being tted orV snapped into the pistonand remaining under .compression while in position.

l With these and other `objects in view, the invention consistsincertain new and novel features yand combination of parts, as will behereinafter more fully explained and pointed 'out in the claims.

In the drawing y sh ment,

owing a Apreferred embodipiston ring L and oil rings.

" Fig., 1 is anenlarged sideview of my improved piston skirt'expandershowing a properly tem'- pered piece of 'wirelbentvto form the smallrloops and `,the large loop,'which latter ts about the bearing of thewrist pin; 1 y j Fig. 2 is a` front view of thesaine;

Flg'.13 lis a side elevation `fpartlyin section of a piston showingthejsplitskirt and showing the expander` snappedinto` position tto .keep`the skirt in its ,expanded position.

' Fig. 4 is a bottom planviewbof piston `show` `ing` the expander inposition;

Fig. 5 is anfenlarged sectional View takenon the1ine,5f-51ofFig. 3. u Q

ferring now to the drawing, andforfthe moment tol Fig.i3,there is showna piston i with the annular yglfoo'ves 2 for` the reception of the seenthe skirt 3 with the bearings 4 for the recepitionofthe wristfpin of` aconnecting rod (not shown). The skirt is 'conventionallyfsplit as at 5,that is,`at right anglesito ,the axis ofthe wrist pin bearings.A i

It will be understood that I do not wish to be limitedto the specificpiston or the manner in skirt pistons. Y

:Referring now to Figs. 1 and 2for the moment, there will bejseen thepiston skirt expander E, rectangular in form (see Fig. 4), whichconsists of the two end portions ii` and the two side portions 1, all ofwhich make up the continuous frame.'

It will be understood thatthe two end portions are similar in"construction and that the two side portions are similar to each other,soa descripbe very efliciently used` with other forms of split *tionl ofone side portion and one end portion `will but the resiliency of thewire will permit it to snap back, so that after the expander is inposi-v tion,l it will remain Vthis way.

It will be noticed that the wire from one edge of the loop extends tothe right to form the horizontal portion 9 and again is bent to form`the smaller eyelet or loop i0 and then extends, as at I I, in ahorizontal plane to the endportion.

There may also `be which the skirt is split,A as these expanders may Ina like manner, still referring to Fig. 1, from the left of the loop 8,the formation is repeated, that is, there are theI horizontal portionI2, th loop I3, and the horizontal portion I4. This bending andarranging of the loops is carried out on the other side portion of theframe, as will be readily understood.

Referring to Fig. 2 for the moment, it will be seen that the end portion1 has the centrally formed loop I5 with the outwardly extending legsthat merge with the two side frame portions. 'I'hese expanders may bemade accurately and their rectangular formation is such that all fourcorners will bear against the four points in the piston skirt, as shownin Fig. 4, to tend to force the split portions of the skirt apart andthus prevent any slapping of the piston in the cylinder.

'Ihe placing of the piston skirt expander in position is but the matterof a moment, as the expander is sufficiently flexible to be compressed,that is, to have the loops compressed, the large loop, however, beingopened to be forced about the bearings 4. After these large loopsencircle the bearings or,`in other words, are snappedl into'place, thereis no possibility of the expander becoming dislodged.

By providing the loops 8, I0, and I3 in the side portions of theexpander, and by also providing the loops I5 at thel opposite ends ofthe expander, there is a great exibility in the expander as a whole anda slight pressure will be exerted both longitudinally of the expanderand transversely thereof. The loops, of course, are of such depth thatthe expander can be easily compressed, and also give the desiredresiliency to the frame as a whole.

By forming the expander in this manner, there is no necessity forproviding adjustment features, which would make the expander costly,and, at the same time, thev flexibility of the expander is such that theskirts'will be expanded in a proper and efficient manner.

As heretofore mentioned, these -expanders can be conveniently andquickly made on jigs and then properly hardened and tempered to providethe desired flexibility and resiliency. Also, they may be made indiierent sizes vor even different shapes to fit differently sizedpistons.

I am aware that it is old to have piston skirt expanders with loops inthe side frames and adjustable features and do notL claim my inventionas such, but what I do claim and desire to secure by Letters Patent is:-

l. An expander for a slotted piston having skirt portions and Wrist pinbearings comprising a spring wire member adapted to be disposed on theinner side of the skirt portions and having loops adapted IU snap overthe wrist pin bearings, the member also having spring loops formed inits vends and sides which are compressed when the expander is placed inposition and thereafter exert an expanding action on the slotted skirtportions.

2. An expander for slotted piston skirts having wrist pin bearings,comprising a spring member endless in form and substantially rectangularin shape and of slightly larger size than the internal'diameter of thepiston skirt, spring loops formed continuously in the expander andadapted to be compressed slightly when the expander .is forced intoposition to thereby thereafter exert an expanding action on the skirt,and additional loops formed in the side members of the ex-` panderadapted to snap over the wrist pin bearings of the piston.

L 3. A piston skirt expander for a slotted piston `comprising a wireendless in form and having side and end portions,rintegral loops formedin the side portions and extending in a plane paralle! with thelongitudinal axis of the expander.

and integral loops `formed in the end portions and extending in planesat right angles tothe longitudinal axis of the expander whereby when theexpander is snapped into position within the piston skirt it-wil1 exertboth a longitudinal an v lateral expandingeffort thereon.

' i y ALBERT W. `WENZIIIL.

